error[E0308]: mismatched types
  --> $DIR/unused-substs-5.rs:15:9
   |
LL |     x = q::<_, N>(x);
   |         ^^^^^^^^^^^^- help: try using a conversion method: `.to_vec()`
   |         |
   |         cyclic type of infinite size

error: aborting due to 1 previous error

For more information about this error, try `rustc --explain E0308`.